The apparent leniency of the sentence for the five migrants was due to their claimed age as it was argued they were too young and would be put at risk by being deported.

However, like thousands of migrants, the gang arrived in Europe with no formal documents. People traffickers advise illegal migrants to destroy formal papers to make it more difficult for the authorities to assess their age.

The district court in Uppsala, north of Stockholm, sparked outrage with the decision and interior minister Anders Ygeman said a new law on age assessment was required.

Mr Ygeman said there was widespread support for the crackdown, after one of the rapists, who claimed to be 17-years-old, was assessed to be 18 by the Swedish Migrant Board.

Minors have greater protection under the law than adult asylum-seekers in Sweden.

And as under-aged asylum-seekers are less likely to be deported, it has sparked concerns migrants will exploit the legal system.

The leading politician said: “The risk is that you do not get the right punishment to the right person, and that people claim to be younger than they are.

“A legal support to make age estimates is important so individuals can’t claim a false age and also to prove protection for juvenile delinquents so that they do not get the wrong penalty.”

A new law could be in place by July 1, however former prosecutor Sven-Erik Alhem said migrants escaping justice would be a persistent problem in the future.

“This will be a be a persistent problem in the future, in these borderline cases. You will never medically able to determine the exact age,” he said.

Adding a policy change was required to ensure a fair legal process, he said: “If a person doesn’t have an identity document, I think you clearly have to place the burden with the individual to prove their identity.”

Without being judgemental, I have a suspicion the use of the term “full confidentiality” smacks of political correctness designed to disarm public opinion by keeping them in the dark of the obvious perhaps?